Wayne Rooney notched his 99th goal for Manchester United as the Premier League champions opened up their title defence with victory over Birmingham.
Rooney tapped home on 34 minutes after his header had hit a post to give Sir Alex Ferguson's men all three points.
It was the highlight of a low-key display from the Red Devils, who are beginning life without Cristiano Ronaldo and Carlos Tevez.
United started confidently with £16million new boy Antonio Valencia providing plenty of pace and threat on the right.
But it was Nani on the left who proved the catalyst for their winner, linking up beautifully with Patrice Evra before crossing for Rooney.
The England man got up really well to beat Hart with a header that struck the base of a post before rebounding into his path for an easy tap-in.
Birmingham, who will play much worse this season and win, almost hit back immediately as Franck Queudrue had a header cleared off the line by Evra. After the break United were fitful in attack, though Rooney forced Hart into a couple of fine saves and Berbatov had a penalty appeal turned down after a challenge from Carr.
Birmingham gave a debut to new boy Christian Benitez for the final 15 minutes, and he almost made a sensational impact by beating the offside trap to force Ben Foster into a fine low save. Michael Owen came on for United in the closing stages, and had a great chance to crown his debut with a goal deep into stoppage time.
But after being put through by a beautiful chested flick from Rooney, he saw his shot saved by Hart.